Hi everyone, I recently sold my Verizon iPhone 4S 16gb (Model MD276LL) on eBay. A week after shipping it, I received a note from the buyer telling me that he was very angry because I sold him an unlocked AT&T iphone. I told him to send me a screen shot of the "about" page showing the carrier, model, serial, IMEI, ICCID, etc. He did, and it matched the info of the phone I sent. The model clearly shows MD276LL, which is a Verizon iPhone 4S. "Verizon" was visible next to the signal bars in the picture he sent. I KNOW this is a Verizon iPhone because I used it with my Verizon account before selling it. It is not, however, unlocked as he claimed. I replied telling him that the model number clearly shows it's a Verizon phone. He replied telling me that data doesn't work, only wifi, and that he went to a verizon store and "they are clueless and are convinced its an AT&T" (I don't really believe this). He wrote again, this time including a screen cap showing a "SIM not valid" error screen and saying that he got that error with "a valid Verizon SIM card" and that he's going to report me to eBay. I'm not sure what else I can tell this guy to prove that it's a Verizon phone, unless of course, I'm missing something and there's a valid reason why it's not working on his account. Can anyone provide some input here on what he might be doing wrong, or what I can ask him to do? What could be wrong with the SIM card? Maybe he's using an old SIM and needs to use a new one? Is there an easy (and free) way to prove to him and to eBay (in case he files a case against me) that this phone is indeed a valid, activatable Verizon phone? Thanks for your help!